This application claims the priority of German application 197 17 066.8-16, filed in Germany on Apr. 23, 1997, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to an apparatus and a process for making extruded hollow profiles.
Hollow-chamber profiles made of metal are produced by means of extruding using an arbor or special hollow-chamber bottom dies (such as chamber, bridge or spider bottom dies) or welding chamber bottom dies for manufacturing the hollow profile. Struts situated within the hollow profile for stiffening the hollow-chamber profile with respect to torsional strain can be also be pressed along in the extruding operation. Furthermore, volume-filling reinforcements of the hollow-chamber profile to be optionally provided are implemented by fillers to be slid into the hollow profile or corner connectors to be welded into it. In the case of a manufacturing as cut pieces, the hollow-chamber profiles must be cut to the required length by means of a suitable cutting process. This takes place, for example, by means of so-called beam or jet processes, such as laser beam cutting or water jet cutting. In this case, after the cutting-through of the profile side facing the beam or jet, a widening and atomizing of the beam or jet takes place when it enters the interior of the profile. This widening has the result that the remaining energy density of the beam or jet will no longer be sufficient for cutting through another profile wall.
From German Patent Documents DE-AS 1 154 264 and DE-OS 1 959464, processes and arrangements are known for the continuous extruding of continuous profiles having a jacket made of a thermoplastic material and having a core made of a foamed material, the extruding of the thermoplastic material to form a hollow-chamber profile and its filling with the foamed material taking place by means of suitable, particularly concentrically arranged nozzles, in one manufacturing operation. For improving the stability characteristics, an extruded profile produced in this manner is filled throughout with foamed material. From German Patent Document DE-OS 1 959 464, it is known in particular to charge the foamable reaction mixture for forming the foamed-material core into the hollow profile first at a point at which the temperature of the jacket has fallen to a predetermined value.
Based on the above, it is an object of the invention to suggest a process for cutting extruded hollow profiles as well as an extrusion arrangement in the case of which a widening of the beam or jet used for cutting the extruded hollow profile to the required lengths does not take place or at least takes place only to such an extent that the cutting-through of profile walls which follow is not impaired.
For achieving this object, a process is suggested for cutting extruded hollow profiles by means of a high-energy beam or jet moved along with the extruding operation, wherein the interior of the extruded hollow profile is filled with a light-weight material at least at the cutting point or points. According to advantageous further developments of the process of the invention, this light-weight material is an expansive foam mass, such as an aluminum foam or a plastic foam. By placing such a light-weight material as the core material inside the profile at points at which cutting is to take place, the separability of the extruded hollow profile during the cutting to required lengths and the cutting to size of the profile by means of the above-mentioned beam or jet processes is improved since, during the beam or jet cutting, because of the formation of a beam-guiding or jet-guiding wall with the core material, an atomization or widening of the cutting beam or jet is avoided. As the light-weight material for filling the extruded hollow profile, particularly an expansive foam mass is suitable which can be charged into the hollow profile by way of a relatively small nozzle diameter and expands there to the desired dimension. However, the use of non-foaming filler materials is also possible for achieving the effect according to the invention.
In a further development of the invention, the filling of the extruded hollow profile takes place by means of coextrusion so that no separate operation is required for filling the extruded hollow profile.
In a further development of the invention, the filling of the extruded hollow profile takes place by way of an arbor or a welding-chamber bottom die of the extrusion arrangement used for manufacturing the extruded hollow profiles.
For further achieving the object of the invention, an extrusion arrangement is suggested which facilitates the process referred to above. According to the invention, the manufacturing of the extruded hollow profile is therefore permitted by the extruding known per se of a material situated in the extrusion chamber through a bottom die arranged at the head-side end of the extrusion chamber; by the filling of the extruded hollow profile at least at the desired cutting points with a light-weight material; as well as by cutting the extruded hollow profile into the required lengths by means of a high-energy beam or jet moved along with the extruding operation, while still warmed by the extruding process heat and in one operation.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.